AI vaccine protects multiple species

The Journal of General Virology reports that a single vaccine could now be
used to protect humans, birds and mammals against different flu strains and can
be given to birds while they are still in their eggs.

Avian influenza poses a major challenge to scientists developing vaccines
as it can infect a number of different animals, including birds, pets and
people. Now, US researchers have discovered that a vaccine based on a bird flu
virus could be used to protect several species against different influenza
viruses.

"The world is experiencing a pandemic of influenza in birds caused by an
H5N1 virus," said Professor Daniel Perez from the University of Maryland in the
US. "The H5N1 virus also has an unusual expanded host range: not only birds and
humans have been infected but also cats, which are usually resistant to
influenza. To prepare for a pandemic, it would be ideal to have a vaccine that
could be used in multiple animal species."

Researchers found that the central genes or 'backbone' of the H9N2 virus
that infects guinea fowl can protect birds and mice against highly pathogenic
strains of influenza. They modified the virus to make it less pathogenic and
then used it to vaccinate mice. Three weeks after being vaccinated, the mice
were infected with the potentially lethal H1N1 virus - the same virus that
caused the 1918 Spanish flu pandemic. All the vaccinated mice survived with no
signs of disease. Vaccinated mice also survived infection with the deadly H5N1
bird flu virus, again showing no signs of disease.

"Our results show that the H9N2 backbone vaccine can be used to protect
mice against two different, highly pathogenic strains of influenza. We chose
genes from H9N2 influenza for the vaccine because the virus can infect many
different animals, including chickens, mice and pigs," said Prof Perez. "A very
important limitation in the current design of flu vaccines is that they are
usually species specific. Our approach involves a universal backbone that can be
used in several different species, including humans."

More importantly, this live attenuated virus provided effective protection
when it was administered to birds before they had hatched. By vaccinating eggs
against influenza, we could protect wild bird species as well as domestic
chickens against pandemic flu strains, limiting the spread of disease to
humans.